Video signals are transmitted as a series of horizontal lines that are combined to give a two-dimensional picture. There are two types of video signals employed today, progressive and interlaced. Progressive video transmits the lines sequentially. Interlaced video is transmitted as two fields; the first field comprises all of the odd lines and the second field comprises all of the even lines. The two fields of odd and even lines have to be combined into a single frame and this is called de-interlacing. If both fields were acquired at the same time, then the two fields cam be simply combined. However if the two fields are acquired at slightly different times and part of the image is moving, then there will be an artifact called combing or feathering. This is a result of the alternating lines being offset horizontal relative to each other. This artifact needs to be removed during the de-interlacing process. There are numerous algorithms for doing this.
The most widely used algorithms are:                Weaving, which simply combines the lines of the two fields;        bobbing, which doubles the lines of each field so as to create a complete frame;        motion, adaptive switch from weaving to bobbing in areas where motion is detected;        motion interpolation on a pixel-by-pixel basis between two successive odd or even fields to create the missing motion.        
What is needed is a diagnostic tool to diagnose the de-interlacing algorithm being used in a particular display or video processor.
Modern pixilated displays and to some extent CRT displays may demonstrate an artifact know as “jaggies.” Jaggies may arise when a diagonal line is shown on a display with discrete elements, such as pixels. The line then comprises a series of steps, instead of a smooth line. Various signal processing techniques may improve the appearance of the line, but these techniques become difficult as the line approaches the horizontal. These algorithms are effective on video that is changing and moving by interpolating from one frame to the next. Thus a simple static test pattern to evaluate the existence and extent of “jaggies” will not be appropriate.
What is needed is a test pattern providing finer resolution than existing test patterns and enabling an observer to evaluate and quantify the success of the signal processing at removing the “jaggies” and rendering a smooth line.